1. Field of the Invention
This invention pertains to a method of making ice cubes having new steps of control, and to an ice cube maker having a new and improved control for harvest and freeze cycles, and to this control for an ice cube maker.
2. The Prior Art
An ice cube maker having a vertical flat plate gridded evaporator is well known and is in extensive public use. The food and beverage retailers and in particular the fast food chains and restaurants have a significant preference for this type of ice cube maker. It is commercially accepted and in many instances preferred.
The leading example of this general type of ice cube maker is made by The Manitowoc Company, Inc. of Manitowoc, Wis., and is quite well documented in U.S. Pat. No. 3,430,452 of Mar. 4, 1969.
Another example of this type of cuber is made by Mile High Equipment Company of Denver, Colorado and is documented in U.S. Pat. No. 4,341,087 of July 27, 1982. This patent has an extensive discussion on the merits of this general type of ice cube maker.
Despite the commercial acceptance and preference for this type of ice cube maker, there have been problems with the control of the freezing and harvest cycles, amongst other things.
Typically, this type of ice cube maker will be in a freeze cycle for 8-12 minutes and will then switch to hot gas defrost to loosen the cubes from the evaporator so that the cubes can be ejected from the evaporator. Timer controls do not work well because the specific incoming water temperature, line voltages, and ambient temperatures are unpredictable. Many various schemes of control have been tried and found to still give problems.
Most recent examples of a controls for this type of machine have been developed by Manitowoc and are disclosed in U.S. Pat. No. 4,480,441 of Nov. 6, 1984 and U.S. Pat. No. 4,550,572 of Nov. 5, 1985. The first is an electro-mechanical device and is thought to be commercialized but the second device has not been seen on Manitowoc products.
Other patents having ice cube makers of this general type include: U.S. Pat. No. 3,913,349, Johnson; U.S. Pat. No. 3,964,270, Dwyer; U.S. Pat. No. 3,144,755, Kattis.